Eschenmoser烯化反应
中性加热条件下吖丙啶基腙通过重氮中间体消除制备烯烃的反应。产物为更多取代基的烯烃。利用BuLi作碱可以在低温下进行【J Am Chem Soc., 1980, 102, 774】。此反应可以制备 Bamford-Stevens反应和Shapiro反应不能得到的三取代烯烃【Tet Lett., 1984, 25, 271】。
Rh2(OAc)4催化下，α-烯丙氧基酮腙通过Rh配位卡宾中间体得到Z-烯基烯丙氧醚，接着进行Claisen重排得到反式二取代γ-不饱和酮或醛。【J Am Chem Soc., 2002, 124, 12426】（7少画了一个苯基，感谢葛树升指正）
反应操作
anti 2,3-Diphenyl-4-pentenal (10). To a Schlenk tube with Rh2(OAc)4 (2.5 mg, 0.0057 mmol) underN2 was added DCE (3 mL) and hydrazone 7 (101.9 mg, 0.277 mmol). The tube was sealed and the mixture was stirred at 130 ℃ till completion (TLC 18:1, pentane-ether) and passed through a silica pad and evaporated in vacuo. Flash chromatography (25:1, pentane-ether) gave 57 mg, 87% of 10, mp 101–103.5 ℃ (from pentane).
【J Am Chem Soc., 2002, 124, 12426】
相关文献
1 Eschenmoser A Helv Chim Acta 1972 55 1276
2 Eschenmoser A Org Syn 1976 55 114
3 Evans DA J Am Chem Soc 1980 102 774
4 Collum DB Tet Lett 1984 25 271
5 Kirmse W Eur J Org Chem 1998 1 201
6 Stolz BM J Am Chem Soc 2002 124 12426
编译自：Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, 141-142.
相关反应